Treatment of heavy petroleum oils

ABSTRACT

Metal and asphaltene-containing heavy petroleum oils are subjected to high temperature steam treatment and then contacted with a deasphalting solvent. The product is particularly suited for further catalytic treatment.

Wilson et al.

TREATMENT OF HEAVY PETROLEUM OILS Inventors: Raymond F. Wilson; Edward L.

Cole, both of Fishkill, N.Y.

Assignee: Texaco Inc., New York, NY.

Filed: Dec. 23, 1971 Appl. N0.: 211,773

References Cited UNITED STATES PATENTS 2/1957 Pew et a1. 208/187 Dec. 18, 1973 2,825,678 3/1958 Jahnig et a1 208/187 3,565,791 2/1971 Urquhart 208/187 3,637,483 l/l972 Carey 208/86 2,235,639 3/1941 Koch 208/188 Primary Examinerl-lerbert Levine Att0meyThomas H. Whaley et al.

[57] ABSTRACT Metal and asphaltene-containing heavy petroleum oils are subjected to high temperature steam treatment and then contacted with a deasphalting solvent. The product is particularly suited for further catalytic treatment.

12 Claims, No Drawings ts p a d .thssstaltst.rs qatss in, he a" WIHFEPHQW .sii sle rs-r In the refining of petroleum it is conventional to distill a crude oil to remove valuable lighter boiling fractions such as naphtha, kerosine and light and heavy gas oils. The still residue is a heavy oil containing higher boiling hydrocarbons and is contaminated with asphaltenes and compounds containing sulfur, nitrogen and metals which make such an oil undesirable as a fuel. In

order to remove the sulfur or nitrogen or to convert the heavy residue into lighter more valuable products, the oil is ordinarily subjected to a catalytic treatment. This is conventionally done by contacting the oil at elevated temperature with a particulate catalyst. Unfortunately, 2Q

unlike distillate stocks which are substantially free from asphaltenes and metals, the presence of asphaltenes and metal-containing compounds in the heavy oil leads to a relatively rapid reduction in the activity of the catalyst to below a practical level. The presence of these materials in the charge stock results in the deposition of metal-containing coke on the catalyst particles which prevents the charge from coming in contact with thecatalystand thereby in effect, reduces the catalyst activity. Eventually, the on-stream period must be in- Regeneration of the catalyst is accomplished by sweeping the reaction zone with an inert gas to remove combustible vapors and then introducing an oxygencontaining gas under carefully controlled conditions to oxidize the deposited carbon or coke without subjecting the catalyst to extremely high temperatures. This treatment results in the removal of the carbon deposit from the surface of the catalyst, and the on-stream period may be resumed with a catalyst of restored activity. However, the metals deposited on the catalyst are not removed by the combustion and gradually the metal buildup on the catalyst is sufficient to deactivate the catalyst to an unsatisfactory level. When this stage is reached the catalyst activity cannot be restored by ordinary methods and it becomes necessary to remove the catalyst from the reaction zone and replace it with fresh catalyst.

It is therefore an object of this invention to remove asphaltenes and metal containing compounds from heavy petroleum oils. Another object is to convert heavy petroleum oils into more valuable products such as fuel oils or oils suitable as charge stocks for catalytic processes. Another object is to prolong the on-stream periods of catalytic treatment of heavy petroleum oils. These and other objects will be obvious to those skilled According to our invention, a process is provided for 6 the removal of asphaltene contaminants from heavy petroleum fractions containing same which comprises .forming a dispersion of said fraction with H 0 at a temperature between 750 F. and 850 F. cooling the reaction product and contacting the H 0 treated fraction with a member of the group consisting of low molecular weight paraftins containing 3-l0 carbon atoms,

N-methyl-Z-pyrrolidone and furfural.

The charge stocks used in the process of this invention are residue-containing oils such as crude petroleum oils, atmospheric residua, vacuum residua, shale oil, tar sand oil and the like, of which asphaltenes and metal-containing compounds comprise a significant portion.

The charge stock is contacted with water at a temperature of at least 750 F. preferably 750 to 850 F. since, above about 850 F. undesirable coke formation takes place. The pressure may be atmospheric or super atmospheric, for example up to about 1,000 psig. The oil and water (steam) are passed through a zone wherein they come into intimate contact to form an oilsteam dispersion. The reaction zone may be either in the form of an elongated tubular zone through which the reactants are passed under conditions of turbulent flow or it may be in the form of a vessel tilled with an inert packing such as glass beads or Berl saddles. The reaction mixture is heated to a temperature above 750 F. and maintained at that temperature for at least about 7% hour preferably from l-2 hours so that upon cooling a stable water-asphaltene emulsion is formed. The entire effluent may be subjected to further treatment or the emulsion, which has a grease-like consistency, may be separated from the treated oil by filtration, sedimentation or decantation and the treated oil may then be subjected to stripping to remove residual traces of water. If desired the emulsion may be dried and metals recovered therefrom.

It is important that the H 0 treatment of the oil be effected at a temperature between 750 and 850 F. under conditions that a dispersion is formed. The dispersion permits intimate contact of the H 0 and the oil and a temperature of at least 750 F. is necessary as, if the treatment takes place below that temperature, the formation of a stable water-asphaltene emulsion does not take place on condensation of the steam.

Pressure in the H 0 treating zone may range between atmospheric and about 1000 psig, a preferred range being atmospheric to 200 psig. The hydrocarbon oil feed may be introduced into the reactor at a rate of O.55.0 volumes of oil per volume of reactor space per hour, preferably 0.5-3.0 v/v/hr. The liquid hourly space velocity of the water should range between 0.1 and 5.0 v/v/hr. preferably 0.2-3.0 v/v/hr.

After cooling the treated oil is subjected to contact with a low molecular weight paraffin containing from 3 to 10 carbon atoms, preferably 3-8 carbon atoms as for example propane or isobutane or with N-methyl-2- pyrrolidone or furfural for the removal of residual asphaltenes. This treatment may be effected in the presence or absence of the water-asphaltene emulsion.

The deasphalting treatment preferably is effected at a temperature between F. and 300 F. although temperature of 50 F. to 400 F. may be used. Pressures of from atmospheric to 400 psig may be used, pressures of from 0 to 50 psig being preferred. The solvent, that is the low molecular weight paraffin, N-methyl-2- pyrrolidone or furfural may be used at a solvent to oil ratio of from 0.5 to 10 liquid volumes of solvent per volume of oil, a preferred ratio being from 1.0 to 3.0.

When the deasphalting treatment is carried out after removal of the stable water-asphaltene emulsion, the solvent-oil layer is separated from an asphaltic layer and the solvent is removed from the oil by distillation therefrom. When the deasphalting treatment is carried out on the cooled treated oil in the presence of the water-asphaltene emulsion, three layers are formed on settling, a solvent-oil layer, a water layer and an asphaltic layer. As in the case of deasphalting after separation of the water-asphaltene emulsion, the solvent may be removed from the oil by distillation therefrom and recycled to the deasphalting zone. The water may be recycled for admixture with additional fresh feed. If desired, the asphaltic residue may be treated for the recovery of metals therefrom.

The following examples are given for illustrative purposes only.

EXAMPLE I In this example the feed is an Arabian Atmospheric Reduced Crude having the following characteristics:

TABLE I Gravity, API l3.4 Sulfur, wt. 3.2 Carbon Residue, wt. l0.l7 Asphaltenes, wt. 3.22 Nickel, p.p.m. Vanadium, p.p.m. 25

In Run A, the charge is treated with H O in a reactor packed with berl saddles and the treated oil is contacted with n-pentane in the presence of the waterasphaltene emulsion. In Run B, the charge is not subjected to any treatment prior to deasphalting with npentaneData on the runs appear below:

The above results show that the high temperature treatment makes the oil more susceptible to improvement than the untreated oil.

EXAMPLE II The charge in this example is a Lago Medio Atmospheric Reduced Crude having the following characteristics:

TABLE 3 Gravity, API 19.9 Sulfur, wt. 96 2.0 Carbon Residue, wt. 3b 6.89 Asphaltenes, wt. 2.94 Nickel, ppm

Vanadium, ppm

Run C follows the procedure of Run A of Example I. In Run D, the stable water-asphaltene emulsion is separated from the treated oil by filtration prior to deasphalting. Run E is a substantial duplicate of. Run B of Example I. Data on the runs appear below:

TABLE 4 Run C D E Temperature, F. 800 800 Pressure, psig 0 0 Oil rate, v/v/hr L0 1.0 Water rate, v/v/hr 0.33 0.33 Yield, wt. chg

Oil l00.0 94.7 Solid 0 5.3 Water treated liquid Sulfur, wt. l.94 Carbon residue, wt. 6.55 Nickel, ppm l4 Vanadium, ppm I Water treated solid Nickel, ppm ll8 Vanadium, ppm 807 Deasphalting Conditions Temperature, F. 70 70 70 n-C loil ratio l0 l0 l0 Yields, liquid wt. 74.0 89.0 89.9 solid, wt. 9.2 6.8 6.0 Liquid Sulfur, wt. 1.83 l.75 1.82 Carbon residue, wt. 3.46 3.53 5,03 Nickel, ppm 5 5 7 Vanadium, ppm 41 35 101 Solid Sulfur, wt. 3.5 4.4 4.2 Nickel, ppm I27 I79 I99 Vanadium, ppm I420 2060 2l40 These results show that the process of Run C may be used to reduce the metal content of the oil significantly. Run D shows that a slightly larger amount of metals can be removed if the water-asphaltene emulsion is separated from the treated oil eg by filtration prior to solvent deasphalting.

The product oil may be used directly as a fuel or may be subjected to further catalytic treatment for conversion into more valuable products.

One method of converting the oil into more valuable products is by catalytic cracking whereby the oil is contacted with a particulate catalyst in a fluidized system as for example in the apparatus disclosed in U. S. Pat. No. 3,433,733.

Another method for converting the oil is by contacting the oil with hydrogen in the presence of a catalyst. The hydro-catalytic treatment of the treated oil, which may for example be either a hydro-desulfurization or a hydrocracking, is carried out by contacting the treated oil in the presence of added hydrogen having a purity of about 60-95 percent with a catalyst at elevated temperature and pressure. Reaction conditions include temperatures between about 500 and 900 F. and pressures between about 300 and 3,000 psig. Preferred temperatures are from about 650 to 850 F. and preferred pressures range from about 500 to 1500 psig. The oil may be passed through the reaction zone at a space velocity between about 0.2 and 5.0 volumes of oil per volume of catalyst per hour, preferably between about 0.5 and 2 v/v/hr. with a hydrogen rate of between about 500 and 10,000 standard cubic feet per barrel of oil preferably between about 750 and 5000 SCFB.

The catalyst may be used as a slurry or in the form of a fixed bed, a fluidized bed or a moving bed and the reactant stream may be passed upwardly or downwardly through the reaction zone. Preferably the catalyst is in the form of a fixed bed of pellets, and the reactant stream is passed downwardly through the catalyst bed.

The hydroconversion catalyst generally will comprise a group VIB metal and a group VIII metal usually as the -.oxide .on a support. When the principal hydroconvertionization treatment for the removal of alkali metal ion and the introduction into the zeolite structure of hydrogen ion. Advantageously the alkali metal is removed by subjecting the zeolite to ion exchange with a solution of an ammonium compound followed by heating to dry and then calcination. The calcined zeolite is subjected to a second ion exchange with a solution of an ammonium compound and then dried. This treatment results in a zeolite having an alkali metal content of less than about 1 percent by weight.

The hydroconversion catalyst should contain between about 2 and percent by weight of the group VIB metal and between about 5 and 40 percent by weight of the group VIII metal. Suitable combinations are nickel and molybedenum, nickel and tungsten and cobalt and molybdenum. A particularly suitable catalyst for the hydrocracking of a treated oil which contains more than 100 parts per million nitrogen comprises 3 to 8 percent nickel, to 30 percent tungsten on a support comprising to percent decationized zeolite Y, 50 to .75 percent silica and 5 to 20 percent alumina. Advantageously, the catalyst is sulfided prior to use.

Other modifications and variations of the above invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A process for the removal of asphaltene contaminants from a heavy petroleum fraction containing same which comprises forming a dispersion of said fraction with H O at a temperature between 750 F. and 850 F., cooling the product to form an H O-treated heavy petroleum fraction of reduced asphaltene content and a stable water-asphaltene emulsion and contacting the H 0 treated fraction with a solvent selected from the group consisting of low molecular weight paraffins containing 3-l0 carbon atoms, N-methyl-Z-pyrrolidone and furfural.

2. The process of claim 1 in which contact of the treated fraction with the solvent is effected at a temperature between 50 F. and 400 F.

3. The process of claim l in which the stable waterasphaltene emulsion is formed on cooling said product to a temperature below 400 F.

4. The process of claim 3 in which the solvent con tacting is effected in the presence of said emulsion.

5. The process of claim 3 in which the emulsion is removed prior to contacting the H 0 treated fraction with solvent.

6. The process of claim 1 in which the solvent is N-methyl-Z-pyrrolidone.

7. The process of claim 1 in which the solvent is a low molecular weight paraffin containing 3l0 carbon atoms.

8. The process of claim 1 in which the solvent deasphalted oil is subjected to catalytic treatment at a temperature between 700 F. and 950 F.

9. The process of claim 8 in which the catalytic treatment is cracking.

10. The process of claim 8 in which the catalytic treatment is hydrocracking.

11. The process of claim 8 in which the catalytic treatment is hydrodesulfurization.

12. The process of claim 1 in which the heavy petroleum fraction is introduced into a dispersing zone at a rate between 0.5 and 5.0 volumes of heavy petroleum fraction per volume of dispersing zone per hour and the B 0 is introduced at a rate between 0.1 and 5.0 v/v/hr. i 

2. The process of claim 1 in which contact of the treated fraction with the solvent is effected at a temperature between 50* F. and 400* F.
 3. The process of claim 1 in which the stable water-asphaltene emulsion is formed on cooling said product to a temperature below 400* F.
 4. The process of claim 3 in which the solvent contacting is effected in the presence of said emulsion.
 5. The process of claim 3 in which the emulsion is removed prior to contacting the H2O treated fraction with solvent.
 6. The process of claim 1 in which the solvent is N-methyl-2-pyrrolidone.
 7. The process of claim 1 in which the solvent is a low molecular weight paraffin containing 3-10 carbon atoms.
 8. The process of claim 1 in which the solvent de-asphalted oil is subjected to catalytic treatment at a temperature between 700* F. and 950* F.
 9. The process of claim 8 in which the catalytic treatment is cracking.
 10. The process of claim 8 in which the catalytic treatment is hydrocracking.
 11. The process of claim 8 in which the catalytic treatment is hydrodesulfurization.
 12. The process of claim 1 in which the heavy petroleum fraction is introduced into a dispersing zone at a rate between 0.5 and 5.0 volumes of heavy petroleum fraction per volume of dispersing zone per hour and the H2O is introduced at a rate between 0.1 and 5.0 v/v/hr. 